1. Technical Field
The present disclosure relates to surgical adhesives and sealants. More specifically, this disclosure relates to fast curing biocompatible compositions based on aromatic diisocyanates.
2. Description of the Related Art
In recent years there has developed increased interest in replacing or augmenting sutures with adhesive bonds. The reasons for this increased interest include: (1) the potential speed with which repair might be accomplished; (2) the ability of a bonding substance to effect complete closure, thus preventing seepage of fluids; and (3) the possibility of forming a bond without excessive deformation of tissue.
Studies in this area, however, have revealed that, in order for surgical adhesives to be accepted by surgeons, they must possess a number of properties. First, they must exhibit high initial tack and an ability to bond rapidly to living tissue. Secondly, the strength of the bond should be sufficiently high to cause tissue failure before bond failure. Thirdly, the adhesive should form a bridge, preferably a permeable flexible bridge. Fourthly, the adhesive bridge and/or its metabolic products should not cause local histotoxic or carcinogenic effects.
A number of adhesive systems such as alkyl cyanoacrylates, polyacrylates, maleic anhydride/methyl vinyl ethers, epoxy systems, polyvinyl alcohols, formaldehyde and gluteraldehyde resins and isocyanates have been investigated as possible surgical adhesives. None has gained acceptance because each fails to meet one or more of the criteria noted above. The principal criticism of these systems has been the potential toxicity problems they pose.
Isocyanate-based adhesive/sealant compositions are disclosed, for example, in U.S. Pat. Nos. 5,173,301; 4,994,542; and 4,740,534, the disclosures of which are incorporated herein in their entirety by this reference.
It would be desirable to provide novel metabolically-acceptable bioabsorbable diisocyanate-based adhesives and in particular metabolically-acceptable surgical adhesives. It would also be desirable to provide metabolically-acceptable surgical adhesives which are biodegradable. It would also be desirable to provide a method for closing wounds in living tissue by use of novel, metabolically-acceptable surgical adhesives which are low in toxicity as a consequence of their physical properties.